Megasoma janus is very similar to the Actaeon beetle. It was previously considered as a subspecies of the former because of its shiny elytra, short and inwardly curved thoracic horns. It was not recognized as an independent species until 2002 with three subspecies: Janus, Ramirezorum and Fujitai. Janus is the god who guards the gates of the past year and the coming year in Roman mythology.